#集合的运算
a=set([10,20,30])
b=set([20,30,40])
set1=a&b
set2=a|b
set3=a-b
set4=a^b
set5=set1<a
set6=a<set2
print('set1=',set1)
print('set2=',set2)
print('set3=',set3)
print('set4=',set4)
print('set5=',set5)
print('set6=',set6)